Flash Flood Early Warning System: Study of Effectiveness and Efficiency

Flash Flood take place recurrently in the Northeast Area (Haor Area) of Bangladesh. Flash floods in the months of April-May destruct the main crop Boro rice almost or just before the harvest. Forecast of flash flood for few or several days may be very useful in harvesting the Boro rice early even before complete maturity so that farmers can capture at least part of the crop for their livelihood round the year or take necessary preparedness to save the crop.

Introduction

Bangladesh is an area of low-lying ground adjacent to a river, formed mainly of river sediments and subject to flooding every year; physically, naturally and geographically Bangladesh is highly exposed to the natural disaster. World's one of the largest and active Ganges, Brahmaputra and Meghna basin which cover only 7% of this nation state where 93% outside this country but among the total flow 70% pass through this country (BWDB). The southern Bay of Bangle to the northern Himalayas Mountain are main triggering factor of natural calamities.

The country loss large amount of its Gross Domestic products (GDP) due to the natural Disaster because of low floodplain with high socioeconomic and physical vulnerability. Flood is the most common natural disaster of this country. It is a frequent phenomenon that occurs every year and damage a large share of our economy. Because of topographical location we are experienced three type of flood. One is the monsoon flood that happen in the rainy season for the heavyweight rainfall.

Changes the intensity of rainfall are the main reason of flood. Our river was degrading because of the increasing the rainfall intensity. There are also quite a few reason of the flood. The storm surge is the cause of flood in our coastal areas which called costal flood, which occurs once, or more on a year. Flash flood is another type of flood which occurs mainly in northeastern low land part of the country. In local language that low land part are called Haor. In different condition and the different economic pattern with different ecological setting, the life of livelihood is different. The Boro production in haor cover 13% rice production which boro cover 54% of total rice demand of Bangladesh.

People can grow in a single Boro season in haor area. They are mostly reliant on the Boro rice over the year. These boro rice not only feed them but also the life and livelihood of haor people and they are mostly reliant on this rice production. People also catch fish and doing the secondary job on the time of monsoon July to October, without Boro production. Because of its geological location and altitude of the land the haor is submerged every year in a time of July to November. Fishing is the only way to leads their livelihood when crops land submerged under water.

Previous year we can see a flash flood, which go above the 100-year return period. In haor area, the water came last week of the April or first week of the May but previous year its came about one month before its normal condition. In haor area flash flood occur almost every year in even we have seen the flash flood in the year of 2000, 2002, 2004, 2010, 2016 and 2017. Two Billion USD is projected cost of 2000 flood most of them are cover flash flood. Every time its carry a large amount of money. Flood cover almost five district in the year of 2010 but all haor are not inundated.

Every disaster is a lesson for our future development. If the development does not take into account the intensity, frequency and other factors of disaster, it is not effective. As a student of disaster science and management we must learn disaster for better learning, this is an opportunity for us to learn the flash flood and find the potential solution to this disaster.

For better learning to a disaster or extreme event, we must need to study on damage and loss assessment. For this, it is necessary to collect information about the disaster and visit the affected area in order to collect people's ideas and concepts. In this study, we will select a study area with the Tahirpur upazila near Saneer Haor. Saneer haor is a great example for us that the people are trying to protect their crop with their own effort and resource. And they can able to protect their crop more than 20 days from flash flood.

Therefore, Saneer haor is a great example for us thus why we choose this area for our study. (Md. syedur rahaman, 2017)

Research objectives

The main objective of this study is to evaluate the effectiveness and efficiency of existing flash flood early warning dissemination channels and to find out the best suited channel for haors area. The specific objectives of this study are:

1. To evaluate existing early warning dissemination channels.
2. To find out the best suited channels for haors area.

Research Questions

Throughout the current research, the following questions will be answered:

1. What are the existing early warning dissemination channels?
2. How well those channels disseminate messages?
3. What would be the best suited dissemination channels?
4. Which contents the message should provide?
5. Study area

Haor is the result of bowl-shaped large tectonic depression. The north-eastern part of the country are the bowl-shaped lower land and named as the Haor and it covers parts of the Sunamganj, Moulvibazar and Habiganj districts, and stretches as far as the Kishoreganj and Netrokona districts. The Haor Basin is estimated to stretch over an area of between 4450 square kilometers and 2. 5 million hectares. It is further estimated that the total area of haor-type wetlands throughout Bangladesh exceeds 8 million hectares (source Banglapedia).

The basin includes about 47 major haors and some 6,300 beels of varying size, out of which about 3,500 are permanent and 2,800 are seasonal. The plains remain flooded for about 7 to 8 months. During the rainy season, the haors turn into a vast inland sea within which the villages appear as islands. The entire Sunamganj district, major portion of Habiganj district, some parts of Sylhet Sadar upazila and Moulvibazar district are covered by many haors. In greater Sylhet the most prominent haors are Soneer haor, Hail haor, Hakaluki haor, Dekar haor, Maker haor, Chayer haor, Tanguar haor, and Kawadighi haor. The Haor Basin is surrounded by the mountain ranges of India, with Meghalaya to the north, Tripura and Mizoram to the south, and Manipur and Assam to the east.

The About 300 families are living this village. Tahirpur is the sub district of Sunamganj, with 7 unions 122 village and 242 moholla the Tahirpur is the poor country respect to the other part of the country. According to the 2011 census 37931 family live in this upazila. Saneer Haor is one of the largest haor located in the Tahirpur upazila. It is known as 'Paddy Mine' to the local people. Boro rice has been planted in 22,000 acres of land. This year most of the haor are affected severely by flash flood Saneer haor is one of them. I have seen some different characteristics of this haor in flooded situation.

This haor is located near the Meghalaya range but it was flooded 20 days later than other haor. The local political person and the villagers work for protect the haor as the can. However, cannot protect their food that they eat over the year. This different characteristic is attracted me to study with the people associate with the Saneer haor. For collecting the primary data, I visited the Sulemanpur a village like an island in the rainy season which was stand beside the Saneer Haor.

Methodology KII (Key Informant Interviews)

Key informant interviews are qualitative in-depth interviews with people who know what is going on in the community. The purpose of key informant interviews is to collect information from a wide range of people—including community leaders, professionals, or residents—who have first-hand knowledge about the community. These community experts, with their particular knowledge and understanding, can provide insight into the nature of problems and give recommendations for solutions. The following are three common techniques used to conduct key informant interviews:

• Telephone Interviews
• Face-to-Face Interviews
• QuestionnairesKII (Key Informant Interviews): Key informant interviews are qualitative in-depth interviews with people who know what is going on in the community. The purpose of key informant interviews is to collect information from a wide range of people—including community leaders, professionals, or residents—who have first-hand knowledge about the community.

These community experts, with their particular knowledge and understanding, can provide insight into the nature of problems and give recommendations for solutions. (Wyse, 2011)The following are two common techniques used to conduct key informant interviews:

• Telephone Interviews
• Face-to-Face Interviews

Through KII method, I will collect data from past or present key professionals of BNCC (Bangladesh National Cadet Corps) Office, Red Crescent Society, Rover Scout, Fire Service and Civil Defense (FSCD) of Dhaka. They will give very useful and valuable information regarding my research objective and research question. This KII will last between two and three hours and will be conducted either face to face or through video conferencing technology, using a semi structured interview guide with focused attention on historical development, key turning points, successes and failures, future directions and current impediments of voluntary activities in Dhaka city.

Interviews will be conducted by a team of two or three interviewers where one interviewer will take the lead responsibility while the secondary interviewers will manage time, take notes, ensuring that all questions from the interview guide will be addressed and, when appropriate, asked for more detail. And for this KII, I will use non-probability (purposive or judgments) sampling. Because professionals who cannot speak freely should be excluded from KII. (UCLA, 2012)

FGD (Focus Group Discussion)

A focus group discussion (FGD) is a good way to gather together people from similar background or experiences to discuss a specific topic of interest. In broad sense, FGD is in-depth group interviewing.

The group is usually of 8-12 persons and this discussion lasts for 1:30 to 2 hours. The participants are motivated but not guided to discuss on the relevant topic. The group of participants is guided by a moderator (or group facilitator) who introduces topic for discussion and helps the group to participate in a lively and natural discussion amongst themselves. FGD session needs to be prepared carefully through identifying the main objective of the meeting, developing key questions, developing an agenda, and planning how to record the session. By using this method, I will collect data related with my research objective and research question. This FGD will be conducted with the active members of urban voluntary activities in Dhaka city.

The purpose of this FGD is to obtain helpful information about the activities of these urban volunteers such as what types of roles they are playing at present for earthquake response; how efficiently they are being trained; procedures of their response; challenges faced by them etc. Because we are interested in obtaining information about the collective rather than the experience or perception of individual members. (The overseas Development Institute, 2009)

Questionnaires: can be either devised by the researcher or they can be based upon some readymade index. If you choose to design your own questionnaire for self-completion, then the rules governing the style and layout are the same as those for designing a questionnaire for a postal survey. There are now many pre-existing questionnaires covering a wide range of conditions and therapy areas as well as quality of life instruments and satisfaction measures. Some of these are designed for self-completion, others are designed to be administered by an interviewer. There are obvious advantages to using such questionnaires, including the fact that many of these have already been well validated and tested for reliability, and there may well be normative data available as a baseline for you to compare your results with. (Nigel Mathers, 2009)